SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5381b709090de8b2cce4dba678f79f06fec7a1024a0e83cb0d6c1e47775775f3' 
  AND token = 'LhpnmVftMuG2z4zEQCGB0d4vLQ+bJo5mhjbBc0w3lYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}